QingShen granules activates mitophagy to suppress renal tubular epithelial-mesenchymal transition via the miR-23b-5p/Nrf2/PINK1 axis.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE: Renal fibrosis (RF) is a pivotal pathological process in chronic kidney disease (CKD), driven by tubular epithelial-mesenchymal transition (EMT). Although Qingshen Granules (QSG) demonstrate clinical efficacy against CKD, their anti-fibrotic mechanisms, particularly concerning mitophagy regulation, remains poorly defined. AIM OF THE STUDY: This study sought to determine if QSG alleviates renal fibrosis by modulating the miR-23b-5p/Nrf2/PINK1 axis, thereby activating mitophagy, and consequently suppressing renal tubular EMT. MATERIALS AND METHODS: An adenine-induced rat renal fibrosis model and a TGF-β1-induced EMT model in NRK-52E cells were established and treated with QSG or QSG-containing serum, respectively. In vivo, adeno-associated virus was administered via tail vein injection to overexpress miR-23b-5p. Gain- and loss-of-function experiments were conducted in cells using miR-23b-5p mimic/inhibitor, Nrf2 overexpression plasmid, and siRNA. The evaluated parameters included renal function, renal histopathology, ultrastructure, mitochondrial membrane potential, oxidative stress levels, and the expression of relevant proteins and genes. RESULTS: QSG significantly improved renal function in the adenine-induced model rats, alleviated renal tubular injury and collagen deposition, and reversed the aberrant expression of EMT markers. Furthermore, QSG upregulated miR-23b-5p, inhibited Keap1, facilitated Nrf2 nuclear translocation, and thereby activated PINK1/Parkin-mediated mitophagy both in vivo and in vitro. Overexpression of miR-23b-5p mimicked the protective effects of QSG, whereas inhibition of miR-23b-5p or knockdown of Nrf2 significantly attenuated QSG's beneficial effects on mitophagy and EMT. CONCLUSION: QSG activates mitophagy via the miR-23b-5p/Nrf2/PINK1 axis, thereby inhibiting renal tubular EMT and fibrosis progression.